Meet the iTwinge. This handy little skinned device slides up over the bottom half of your iPhone and draws a slow trickle from your battery to power it. Lightweight, the iTwinge comes in at around 1 ounce, works on 3G and 3G S models and will set you back thirty bucks.
Promising to increase your typing speeds and decrease your typo rate, makers of the iTwinge talk a pretty good game. They ask you to give them three to four hours of typing to make a convert of you, and require no additional software for the device to work.